The particular type of chain which includes T-headed pins comprises pin links and center links which, with the pins, are designed to allow the chain to be assembled and disassembled without tools. Most commonly, such chain is used in trolley conveyors and is generally of drop forged iron alloy construction. Recently the links of some chain for use in food processing plants has been of an injection molded engineering plastic. While the tensile strength of such chain is considerably less than that of a comparable chain of drop forged construction, the links are more readily cleaned and do not corrode.
In attempting to provide suitable pins of stainless steel for use in such chain it was discovered that T-headed pins could be made from flat steel strip having a smooth prepared surface, rather than forged of an iron alloy. That is, each T-head of a drop forged pin comprises oppositely projecting tabs or ears of a width which conventionally approaches but does not exceed the diameter of the pin. Tabs of less width and also which project radially of the pin but somewhat angularly of each other are also readily provided by the present invention.
U.S. Pat. No. 2,298,604 shows the trolley conveyor type of chain which has been referred to. A typical drop forged pin is shown as prior art in this application and as will be further described, the pin body has axial, oppositely disposed ridges.
It is an object of the present invention to provide a pin which does not have such ridges and has a smooth surface finish as formed.
It is further an object of the invention to reduce the amount of metal required to comprise the pin.
Another object is to reduce the chain clearance requirements by reducing the required thickness of the tabs.
Another object is to allow the closing seam to be placed out of contact with the moving bearing surface.
Another object is to provide a hollow pin through which attachment bolts or rods may be extended.
In the manufacture of such chain in selected lengths, all the links of each length must be assembled in the same manner which is provided for later without tools. Such assembly of entire lengths for initial manufacture has been unavoidably time consuming, and a large part of the first cost of the chain. The present invention allows such lengths of chain to be assembled with automatic or semiautomatic equipment, or even by hand, at great savings.